Boiler tube fly ash collector



Aug. 4, 1953 c. E. MILLER 2,647,588

BOILER TUBE FLY ASH COLLECTOR Filed Jan. 16, 1950 3 SheetS-Sheet lF/GURE INVENTOR. Carl E. Miller B Mm .45

AGENTS.

Aug. 4, 1953 c. E; MILLER BOILER TUBE FLY ASH COLLECTOR 3 Sheets-Sheet 2Filed Jan, 16, 1950 F/GURE 2 FIGURE 3 INVENTOR.

w m wan 1r. I A w Aug. 4, 1953 c. E. MILLER BOILER TUBE FLY ASHCOLLECTOR 5 Sheets-Sheet 3 Filed Jan. 16 1950 F lGURE 4 F IGURE 5INVENTOR. Carl E. Miller ,m, WM

A 7' TOHNEYS Patented Aug. 4, 1953 UNITED STATES PATENT OFFICE BOILERTUBE FLY ASH COLLECTOR Carl E. Miller, Columbus, Ohio, assignor, bymesne assignments, to Bituminous Coal Research, Inc., Pittsburgh, Pa., acorporation of Delaware Application January 16, 1950, Serial No. 138,806

3 Claims.

This invention relates to fly ash concentration, and more particularlyto a combination fly ash concentrator and a fire tube boiler.

The problem of atmospheric pollution by fly ash and cinders has beensolved to a great extent in the past by the use of various types ofmechanical collectors and concentrators. However, in the prior art,every device which has been suggested or used has materially increasedthe size of the boiler, and the cost of installation. Cost ofinstallation and size are primary considerations in the installation ofany type of boiler. Moreover, the size of the boiler becomes a much moreimportant factor in determining its desirability when the boiler isinstalled in a vehicle, such as a locomotive or a ship, where spaceoften is at a premium. Consequently, a fly ash concentrating orcollecting device which utilizes a considerably smaller amount of spacethan collectors or concentrators in the prior art, is an extremelydesirable addition to the art of smoke abatement.

It is therefore one object of this invention to provide a combinationfly ash concentrator and fire tube boiler.

It is another object of this invention to provide a combination fly ashconcentrator and fire tube boiler which occupies a minimum amount ofspace, and which can be fabricated at a minimum cost, for a particularboiler rating.

It is a further object of this invention to provide such a devicewherein the overall efliciency of the boiler is materially increased.

It is a still further object of this invention to provide such a devicewherein the quantity of fuel consumed is materially reduced.

Various other objects and advantages of this invention will becomeapparent to those skilled in the art upon reading thefollowingspecification in conjunction with'the accompanying drawings inwhich:

' Fig. 1 is an elevation view, partly in section, illustrating thisinvention;

Fig. 2 is a fragmentary perspective view, partly in section, withportions broken away, showing a particular portion of this invention;

Fig. 3 is a fragmentary perspective view, partly in section, withportions broken away, showing a modification of a particular portion ofthis invention;

' Fig. 4 is a fragmentary perspective view, partly in section,with'portions broken away, of a 'further modification of a particularportion of this invention; and

Fig. 5 is a further fragmentary perspective viewof the device shown inFig. 4..

Referring now to the drawings, and more particularly to Fig. 1, a firetube type boiler is indicated generally at I. This particular embodimentis a horizontal return tubular boiler, but it is to be understood thatthe invention is equally adaptable to any other type of fire tubeboiler. In the embodiment shown in Fig. 1, the boiler is provided with astoker 2, a feed hopper 3, and a motor 4. While there has been shown astoker fired, coal burning boiler, oil fired boilers and other forms ofstoker fired boilers are to be considered as coming within the scope ofthis invention. The fire bed is in the general area indicated at 5 andthe hot gases, formed by the combustion of the fuel, flow upwardly andthen through the tubes in the directions indicated by the arrows. Aprimary fly ash concentrator 6 is located in each fire tube 1 near thedischarge end thereof. Breaching 8 conducts the cleansed gases from thefire tubes to the stack 9. In this particular embodiment of theinvention a cyclone air separator I0, with an air tight receptacle llattached thereto, is connected to the discharge side of the fire tubes 1by means of duct l2. The cleansed gases leave the cyclone air separatorat l3 and flow in the direction indicated by the arrows through duct I4,fan l5, and duct [6 into the stack 9.

A concentric pipe l! is fitted within each of the fire tubes 1 near thedischarge end [8 thereof. This concentric pipe is also shown in Figs. 2,3, 4 and 5. Pipes I! are securely fastened in the tube sheet I9, and theupper fire tubes 1 are securely fastened in the tube sheet 23, which ispositioned parallel to tube sheet l9. Tube sheets I9 and 23 are spaced,and the space between them opens into duct [2.

Referring now more particularly to Fig. 2, 24 is a cylindrical member,preferably having a hemispherical end 25 (see Fig. 1) and a flat end 26,which lies in a plane perpendicular to the axis of the fire tube 1. Thegas flow is in the direction indicated by the arrows. Cylindrical member24 is equally spaced from the inner wall 21 of the fire tube l, andwithin which it is secured, by helical vanes 28. It will be apparentfrom Figs. 2, 3, 4 and. 5, that pipe I1 is only slightly spaced fromfire tube 1 at the discharge end l8 thereof, thereby providing a smallannular space 29.

A modification of the device shown in Fig. 2 is shown in Fig. 3. In thismodification, there is provided a similar cylindrical member 24, coaxialwith and secured within the fire tube 1,- However, this particularconcentrator difiers from and having its periphery equi-spaced from thesurface El of the fire tube 1, but lying-in'a plane parallel to theplane in which the ring 8i lies, is a disc 32. Disposed"between the ringand the disc and firmly attached"thei'et'dare a plurality of vanes 33,which areplanar, long'i tudinally extending, and would be-tangent to" acylinder coaxial with said fire tube, but of a smaller diameter thandisc 32.

While this invention has been shown in its preferred embo-zlirn'ents itis to be under-stood that it is not to be consideredflimited' to' themere embodiments disclosed herein. For instance,- the boiler may be 'ofa type other than horizontal return tubular. The stoker could be of anytype; the cyclone a'ir separator i ii could be replaced by anelectrostaticairseparator, and the fuel could be'o'ther than coal, suchas oil or gas. It is essential that there be a pre'ssure dropbetween-the discharge ends user the firetubes "i and the secondaryconcentratoror separator as. However, such a pressure dropni'ight beaccomplished by inean's other than a fani5. For instance, inthe-case-o'fa loc'emot'ive installation, it might be verydesirable-tense a steam jet, utilizing waste steam, thereby providingthe necessary pressure drop lvforeoveifi thecleansed gasesdo notneceshave to go-to the stack, as has been shown butif their heatvalues-are high they n11- "it very well 'go-to an air preheater. I

erniore,'='this invention'is not tobe con limited to the particularembodiments of the-primaryfly ash" concentrating device" as diselosed'inFigs-*1, 2, 3, 4 and'f). The broad concept cf -this invention includesany type of concentrating 1 and separating device which is loat iwithina fire tube and functions to 'con centr' te i'iy ash and separategas fIOlIl' fiyashby' the ash toward the outer periphery of tube'a.rid*'thencef removing the fly ash from re s tuba-while thegreaterfpo'rtionof thegase move toward'the'center of the tube. ln' oper ing thisdevica'the hot fly ashladen" gases p threngh the fire tubesin the directions" indicated by the arrows, and when they" reaehthe concentrator 6are given a whirling motion. Since the particles of fiyasli'or'o'thersolids are heavier than these hot gases; these parti lesare thrown"toward the inner surfaes" of the'tub'e l but continue to travel ina'lon'g'itudina'l' directionln eifect, the path of the gase's'"and" thefly ash i's somewhat of a helix after their direction has be'e n changed bythe primary con-" centra'ctore. -When the gases' a'nd'the' flyashreaclrthe section i 8 of the tube i, the essen es passthro'ugh the'pipell', and

tially thehce out to tl stack; The fly ash; which has a small amen ofgas associated therewith, is sklii fined oif .nougn the annularspace'29"and drawn down into the duct 52, due to the drop in me sy ash Hthei witlie The 1 gases which are associate-(r y asli drops down "intothe" 4 sealed receptacle Ii, while the gases then travel through ductsl4 and it to the stack 9.

In the Various embodiments of the primary concentrator which are shownin Figs. 2, 3, 4 and 5, preliminary concentration is effected inessentially the same manner. In each case, the concentration of fly ashin the exhaust gases is greatly increased in those exhaust gases nearthe inner surface of the tube l and practically eliminated in theinterior, axial zone of the tube 1. Therefore, the interior portion oftube 1 contains practically pure exhaust gas. This is accomplished, ineach case by giving the combined gas and'flyash a twisting motion, theheavier fly ash and cinder particles moving toward the inner surface ofthe tube l, and the lighter exhaust gases moving toward the center axisof the tube.

A true synergistic effect is achieved by means of the novel combinationconstituting this invention. A substantial amount of heat-is transferredin the portions of the tubes 5 between the end portions i8 thereof andthe portions adjacent the ends 25 of the primary concentrators. -Whenthe fiy ash particles are whirled toward the inner surface of the firetubes, in a helical'path; not only is there effected a separation ofgases and ash, but an unexpected, important, additional result isachieved. The fly ash particles, because of their helical path, andbecause they skim along the inner surface of the fire tubes, remove anysoot particles which cling to such inner surface and, consequently, ascrubbing and cleaning action is realized. Since mount of heat thattransferred through tubes is appreciably lowered when a layer so tformed on the inner surfaces of the fire tubes, the removal of this sootlayer by the scrubbing action of the whirling soot particles appreciablyimproves the heat transfer characteristics of the fire tubes, andsubstantially reduces thequanity of fuel required. Therefore, theprimary concentrators, in additio'nto functioning as concentrators andseparators, when combined with fire tubes in thismann'er, function tocleanthe inner surfaces of the fire 'tub'es'.

Moreover, in addition to the fact that the fly ash is eifectivelyseparated from theexhaust' results'in a'savi'n'g in space of as much asappren- Moreoverfrather than" burden the purchaser witha number ofseparate units,'this particular invention may be purchased as acomposite articlewithconsequent savings in-initial purchase cost,maintenance'costs, freight charges, and" sundry other expenses.

Froin'the' foregoing it should be obvious that there has been devised anew 'andnovelcorn"- b nanonwnien results in increased boilerefficienc'yQTeductiOn in size" or the boiler unit, reduction in fuelconsumption of the boiler, reduction in the initial cost of the boilerand reductibn in maintenance cost of the boiler;

Whileit his"inventionhas been described in its preferred embodiment; itis to be understood that the words used are wordsof description.rather"than "of"'li'mitat'i'on, "and that changes within the purview"o'f'theap'p'ended claims may be made without departing from the true scopeand spirit of the invention.

What is claimed is:

1. The combination of, a fire-tube boiler provided with a plurality ofspaced fire tubes therein, each of which said tubes is adapted toconduct hot gases therethrough, and which said tubes, during operationof said boiler, are surrounded by a fluid which is to be heated, and afly-ash collecting system comprising fiy-ash and gas separating andconcentrating means wholly within each of said tubes, whereby there isprovided a relatively clean stream of gas centrally of each of saidtubes and a stream of gas high in fly-ash particle concentrationadjacent the periphery of each of said tubes, means adjacent the end ofeach of said tubes for separately conducting said relatively cleanstream of gas and said stream of gas high in fly-ash particleconcentration, fiy-ash and gas separating means external of said tubes,a conduit connecting said external separating means with said means forseparately conducting said stream of gas high in fiy-ash particleconcentration, and means for producing a fiow of said stream of gas highin fly-ash particle concentration to said external separating means.

2. The structure set forth in claim 1 wherein said external fly-ash andgas separating means is a cyclone air separator.

3. The structure set forth in claim 1 wherein said fly-ash and gasseparating and concentrating means wholly within each of said tubescomprises cylindrical means within each of said tubes and equispacedfrom the inner surface of each of said tubes by a plurality of radiallydisposed, longitudinally extending, helical vanes.

CARL E. MILLER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 538,589 Kemble Apr. 30, 1895 630,023 Baker Aug. 1, 18991,923,498 Nallinger Aug. 22, 1933 1,970,077 Collins Aug. 14, 19342,182,854 Pfeffer et a1. Dec. 12, 1939 2,236,358 Allardice Mar. 25, 19412,370,629 Appeldoorn Mar. 6, 1945 2,391,860 Badenhausen Jan. 1, 19462,415,935 Bullock Feb. 18, 1947 2,515,894 Polk July 18, 1950 2,569,710Fitzpatrick Oct. 2, 1951

